The present invention improves the efficiency of air removal. When a check valve 2202 is removed from the bottom wall portion 16 of a pneumatic fender 10, a check valve insertion hole 2210 in a valve body 2206 is exposed in the bottom wall portion 16. A cylinder part 28 of an air removal jig 26 is detachably connected to the outer peripheral surface 1804 of an annular wall portion 18 so as to position two supporting members 32 each on both sides of a hook 24. When the cylinder part 28 is detachably connected to the outer peripheral surface 1804 of the annular wall portion 18, a magnet 34 on each tip of the supporting members 32 on both sides of the hook 24 attracts an annular end surface 1802 thereto. A state in which the air removal jig 26 is connected to a cap fitting 14 is maintained thereby. A vacuum hose 2 is connected to a male thread member 3602 via an on-off valve 4, and air in the interior of an elastic bag body 12 is removed through the vacuum hose 2, on-off valve 4, male thread member 3602, and check valve insertion hole 2210 by actuating a vacuum pump.